More than half of American adults take vitamins, minerals, herbs, or other nutritional supplements. Some of those products aren’t especially helpful, readers told us in a recent survey, but that aside, don’t assume they’re safe because they’re “all natural.” They may be neither. Here are 10 hazards that we’ve distilled from interviews with experts, published research, and our own analysis of reports of serious adverse events submitted to the Food and Drug Administration, which we obtained through a Freedom of Information Act request. Read and be warned.